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Journal of Allergy
Volume 2012 (2012), Article ID 125367, 5 pages
http://dx.doi.org/10.1155/2012/125367
Clinical Study

Urticaria in Monozygotic and Dizygotic Twins

1Department of Dermato-Allergology Gentofte Hospital 2900 Hellerup, Denmark
2Complex Trait Genetics, Department of Functional Genomics and Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
3Institute of Regional Health Services Research and Odense Patient Data Explorative Network, University of Southern Denmark, 5000 Odense, Denmark
4The Danish Twin Registry, University of Southern Denmark, 5000 Odense, Denmark
5Department of Respiratory Medicine, Bispebjerg Hospital, 2400 Copenhagen NV, Denmark

Received 17 August 2012; Revised 10 October 2012; Accepted 28 October 2012

Academic Editor: William E. Berger

Copyright © 2012 Simon Francis Thomsen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aim. To identify risk factors for urticaria, to determine the relative proportion of the susceptibility to urticaria that is due to genetic factors in an adult clinical twin sample, and to further determine whether the genetic susceptibility to urticaria overlaps with the genetic susceptibility to atopic diseases. Methods. A total of 256 complete twin pairs and 63 single twins, who were selected from sibships with self-reported asthma via a questionnaire survey of 21,162 adult twins from the Danish Twin Registry, were clinically interviewed about a history of urticaria and examined for atopic diseases. Data were analysed with Cox proportional hazards regression and variance components models. Results. A total of 151 individuals (26%) had a history of urticaria, whereas 24 (4%) had had symptoms within the past year. Female sex, (1.46–2.99), ; hay fever, (1.36–2.72), ; and atopic dermatitis, (1.02–2.06), were significant risk factors for urticaria. After adjustment for sex and age at onset of urticaria in the index twin, the risk of urticaria was increased in MZ cotwins relative to DZ cotwins, (0.63–3.18), . Genetic factors explained 45% (16–74%), , of the variation in susceptibility to urticaria. The genetic correlation between urticaria and hay fever was 0.45 (0.01–0.89), . Conclusions. Susceptibility to urticaria is partly determined by genetic factors. Urticaria is more common in women, and in subjects with hay fever and atopic dermatitis, and shares genetic variance with hay fever.